How to define unicode columns on IDS7.3?

Hi! I try to insert Java unicode characters into IDS7.3 on Linux. I use JDBC connection to database. The problem is when I try to insert some local (slovene) characters they are not stored into database. (i.e. there are only ?? characters in database) I setup IDS with default LOCALE settings (en_us) because I didn't find any info about how to setup database to accept unicode chars except the claim that IDS support unicode. Of course there I didn't find also no info how to collate them. Any help appreciated, Damijan